We've just bought a Pilates Power Gym, and I'd love some advice on how to get properly started. I'm really really really out of shape, so starting slow would probably be best. I'd specifically like some knee strengthening exercises, as I've had Patella Femoral Syndrome since I was 12, and my knees now click like an old woman's(I'm 23). Any suggestions? Thanks!

Im not familiar with Patella Femoral Syndrome but Im pretty sure a comfortable stretch is always beneficial.
just make sure you warm up your calves and thighs well enough before you stretch. after all of the muscles surrounding the knees are warmed up then get to the work out.
always keep your knees slightly bent and make sure you cool down after the work out.